"The Linux Kernel 3.15 is now available for the users", announced Linus Torvalds. Just check what Linus wrote on the mailing list:

So I ended up doing an rc8 because I was a bit worried about some
last-minute dcache fixes, but it turns out that nobody seemed to even
notice those. We did have other issues during the week, though, so it
was just as well. The futex fixes and cleanups may stand out, but as
usual there's various other random fixes since rc8 in there too:
mainly drivers (drm, networking, sound, usb etc), networking,
scheduling and perf tooling.
But it's all been fairly small and quiet, which *may* of course be due
to the fact that last week was also the first week of the merge window
for 3.16. That might have distracted some developers. I'm not entirely
convinced I liked the overlap, but it seemed to work ok, and unless
people scream really loudly ("Please don't _ever_ do that again") and
give good reasons for doing so, I might end up doing that overlapping
merge window in the future too if it ends up helping out with some
particular timing issue.....